A communication system comprises a transmitter, a receiver, and a communication channel. The transmitter launches a first signal unto the communication channel. After propagating through the communication channel, the first signal evolves into a second signal. The receiver receives the second signal and seeks to process the second signal so as to retrieve the information embedded in the first signal. If the communication channel is free of dispersion, the second signal will be substantially similar to the first signal. In this case, the difference between the first signal and the second signal is only a delay and a scaling factor, both of which can be easily handled by the receiver using various techniques of timing synchronization and automatic gain control that are well known in prior art. In reality, however, the communication channel is usually dispersive, and consequently the second signal is a distorted version of the first signal (aside from a possible delay and a possible scaling factor). A feedforward equalizer embodied by a FIR (finite impulse response) filter is an apparatus for equalizing the distortion introduced to the second signal due to channel dispersion. Most feedforward equalizers are discrete-time circuits, where a sampling device to convert the received signal into a discrete-time signal. For a high-speed communication system, however, discrete-time feedforward equalizers are very difficult to realize due to the difficulty in implementing a high-speed sampling device. In these applications, continuous-time feedforward equalizers are a good alternative. To date, high-speed continuous-time feedforward equalizers rely on LC circuits. For reference, please refer to the article “An 80 mW 40 Gb/s 7-Tap T/2-Spaced FFE in 65 nm CMOS,” in 2009 IEEE International Solid-State Circuits Conference Digest of Technical Papers, Volume 52, pages 364-365, written by Momtaz and Green, and the references cited therein. While offering good performance, however, LC circuits are expensive. What is needed is a low-cost high-speed continuous-time feedforward equalizer.